diff --git a/README.md b/README.md
index d7335e19..7707d966 100644
--- a/README.md
+++ b/README.md
@@ -1233,9 +1233,9 @@ First, install dependencies:
 
     # Optional: Change bundler install path to be local
     bundle config --local path $(pwd)/.bundle
-    bundle instal
+    bundle install
 
-To build shared library for development use (ensure you have cloned submodules :
+To build shared library for development use (ensure you have cloned submodules) :
 
     bundle exec rake compile
 
diff --git a/temporalio/lib/temporalio/internal/worker/workflow_worker.rb b/temporalio/lib/temporalio/internal/worker/workflow_worker.rb
index 6e194162..10b9ee5c 100644
--- a/temporalio/lib/temporalio/internal/worker/workflow_worker.rb
+++ b/temporalio/lib/temporalio/internal/worker/workflow_worker.rb
@@ -111,7 +111,7 @@ def initialize(
             disable_eager_activity_execution:,
             workflow_interceptors:,
             workflow_failure_exception_types: workflow_failure_exception_types.map do |t|
-              unless t.is_a?(Class) && t < Exception
+              unless t.is_a?(Class) && t <= Exception
                 raise ArgumentError, 'All failure types must classes inheriting Exception'
               end
 
diff --git a/temporalio/lib/temporalio/workflow/definition.rb b/temporalio/lib/temporalio/workflow/definition.rb
index b0643c37..2f21f5e3 100644
--- a/temporalio/lib/temporalio/workflow/definition.rb
+++ b/temporalio/lib/temporalio/workflow/definition.rb
@@ -55,7 +55,7 @@ def workflow_raw_args(value = true) # rubocop:disable Style/OptionalBooleanParam
         # @param types [Array<Class<Exception>>] Exception types to turn into workflow failures.
         def workflow_failure_exception_type(*types)
           types.each do |t|
-            raise ArgumentError, 'All types must classes inheriting Exception' unless t.is_a?(Class) && t < Exception
+            raise ArgumentError, 'All types must classes inheriting Exception' unless t.is_a?(Class) && t <= Exception
           end
           @workflow_failure_exception_types ||= []
           @workflow_failure_exception_types.concat(types)